Quote Originally Posted by Scotty@Advanced View Post
The volume of air entering the turbo is greater than the volume of air exiting the turbo. However the mass of the air into the turbo is the same as the mass of the air exiting the turbo, which mean that the turbo is ingesting more air (flow) than it's outputting, thus more mass per given time (flow) at the inlet than at the outlet, however the air at the outlet is denser and at a higher temperature.

Since air mass entering turbo = air mass exiting turbo the MAF will be measuring the SAME Air density if it is mounted in the inlet or outlet of the turbo... HOWEVER a temperature adjustment needs to be done because the air exiting the turbo is hotter due to the inefficiencies of the turbocharger, so you need to put it in a cool spot.

To test this install a MAF on both inlet and outlet and measure the voltages, they will be very close to each other.

The reason it is a bad idea to put it in the discharge side of the turbo is that the turbo spews microscopic drops of oil into the intake stream and these will collect on the MAF sensor making it read incorrectly, so it will have to be cleaned or replaced frequently.

More things to consider:

Supply side MAFS don't see large temperatures, so by putting it in the discharge side you may be operating it past it's design limitations.
The plastic tube may burst.
The seals on the MAF insert may not hold up to positive pressure.

















However the largest problem with mounting the MAF after the turbo is the small fog oil that leaks past the turbo, overtime this will coat the MAF resistor and give false readings. The older thin wire MAF's burned most of this oil/dirt crap off at shutdown, however the newer thin film MAF sensor don't have that capability so they will periodically need to be cleaned or replaced.


Well put.
The oil that you refer to is going to be my main problem.
However, the MAF is only temporarily there. Soon enough, we will not need the MAF as it will be fully tunned.
The hardware/software that I am utilizing fools the ECU anyways, telling it exactly what the readings are.

Soon enough there will be no necessity for the MAF once the tune is written.

Pictures will be up shortly.